Methods and apparatus for loading a prosthesis onto a delivery system

ABSTRACT

A device for loading a prosthesis onto a delivery system includes a first housing having a central bore. One or more actuators on the first housing may be actuated radially inward to selectively compress a discrete portion of the prosthesis disposed in the central bore.

CROSS-REFERENCE

The present application is a continuation of U.S. patent applicationSer. No. 17/168,818, filed on Feb. 5, 2021, which application is acontinuation of U.S. patent application Ser. No. 16/295,913, filed onMar. 7, 2019, now U.S. Pat. No. 10,940,001 issued on Mar. 9, 2021, whichis a continuation of U.S. patent application Ser. No. 15/890,119, filedon Feb. 6, 2018, now U.S. Pat. No. 10,314,705 issued on Jun. 11, 2019,which is a continuation of U.S. patent application Ser. No. 15/134,164,filed on Apr. 20, 2016, now U.S. Pat. No. 10,016,275 issued on Jul. 10,2018, which is a divisional of U.S. patent application Ser. No.13/904,827, filed on May 29, 2013, now U.S. Pat. No. 9,345,573 issued onMay 24, 2016, which claims the benefit of U.S. Provisional ApplicationNo. 61/653,273 filed on May 30, 2012, the entire contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention generally relates to medical devices and methods,and more particularly relates to devices and methods for loading aprosthesis onto a delivery system. The prosthesis may be any device butin preferred embodiments is used to treat valve insufficiency, such asmitral insufficiency, also referred to as mitral regurgitation. Thedelivery system may be any system used to deliver the prosthesis eitherby traditional surgical implantation methods, or by less invasivepercutaneous catheter or minimally invasive transapical methods.

The heart of vertebrate animals is divided into four chambers, and isequipped with four valves (the mitral, aortic, pulmonary and tricuspidvalves) that ensure that blood pumped by the heart flows in a forwarddirection through the cardiovascular system. The mitral valve of ahealthy heart prevents the backflow of blood from the left ventricleinto the left atrium of the heart, and comprises two flexible leaflets(anterior and posterior) that close when the left ventricle contracts.The leaflets are attached to a fibrous annulus, and their free edges aretethered by subvalvular chordae tendineae to papillary muscles in theleft ventricle to prevent them from prolapsing into the left atriumduring the contraction of the left ventricle.

Various cardiac diseases or degenerative changes may cause dysfunctionin any of these portions of the mitral valve apparatus, causing themitral valve to become abnormally narrowed or dilated, or to allow bloodto leak (also referred to as regurgitate) from the left ventricle backinto the left atrium. Any such impairments compromise cardiacsufficiency, and can be debilitating or life threatening.

Numerous surgical methods and devices have accordingly been developed totreat mitral valve dysfunction, including open-heart surgical techniquesfor replacing, repairing or re-shaping the native mitral valveapparatus, and the surgical implantation of various prosthetic devicessuch as annuloplasty rings to modify the anatomy of the native mitralvalve. More recently, less invasive transcatheter techniques for thedelivery of replacement mitral valve assemblies have been developed. Insuch techniques, a prosthetic valve is generally mounted in a crimpedstate on the end of a flexible catheter and advanced through a bloodvessel or the body of the patient until the valve reaches theimplantation site. The prosthetic valve is then expanded to itsfunctional size at the site of the defective native valve.

While these devices and methods are promising treatments for valvarinsufficiency, they can be difficult to deliver, and difficult to loadonto the delivery system. Therefore, it would be desirable to provideimproved devices and methods for coupling the prosthesis with thedelivery system. At least some of these objectives will be met by thedevices and methods disclosed below.

2. Description of the Background Art

By way of example, PCT international patent number PCT/US2008/0544 0(published as PCT international publication no. WO2008/103722), thedisclosure of which is hereby incorporated by reference, describes atranscatheter mitral valve prosthesis that comprises a resilient ring, aplurality of leaflet membranes mounted with respect to the ring so as topermit blood flow therethrough in one direction, and a plurality oftissue-engaging positioning elements movably mounted with respect to thering and dimensioned to grip the anatomical structure of the heart valveannulus, heart valve leaflets, and/or heart wall. Each of thepositioning elements defines respective proximal, intermediate, anddistal tissue engaging regions cooperatively configured and dimensionedto simultaneously engage separate corresponding areas of the tissue ofan anatomical structure, and may include respective first, second, andthird elongate tissue-piercing elements. The valve prosthesis may alsoinclude a skirt mounted with respect to the resilient ring for sealing aperiphery of the valve prosthesis against a reverse flow of blood aroundthe valve prosthesis.

PCT international patent number PCT/US2009/041754 (published as PCTinternational publication no. WO2009/134701), the disclosure of which ishereby incorporated by reference, describes a prosthetic mitral valveassembly that comprises an anchor or outer support frame with a flaredupper end and a tapered portion to fit the contours of the native mitralvalve, and a tissue-based one-way valve mounted therein. The assembly isadapted to expand radially outwardly and into contact with the nativeheart tissue to create a pressure fit, and further includes tensionmembers anchoring the leaflets of the valve assembly to a suitablelocation on the heart to function as prosthetic chordae tendineae.

Also known are prosthetic mitral valve assemblies that utilize a clawstructure for attachment of the prosthesis to the heart (see, forexample, U.S. patent application publication no. US2007/0016286 toHermann et al., the disclosure of which is hereby incorporated byreference), as are prosthetic mitral valve assemblies that rely on theapplication of axial rather than radial clamping forces to facilitatethe self-positioning and self-anchoring of the prosthesis with respectto the native anatomical structure.

Another method which has been proposed as a treatment of mitral valveregurgitation is the surgical bow tie method, which recently has beenadapted into a minimally invasive catheter based treatment where animplant is used to clip the valve leaflets together. This procedure ismore fully disclosed in the scientific and patent literature, such as inU.S. Pat. No. 6,629,534 to St. Goar et al., the entire contents of whichare incorporated herein by reference.

Other relevant publications include U.S. Patent Publication No.2011/0015731 to Carpentier et al. and WO 2011137531 to Lane et al. Whilesome of these devices and methods are promising, there still is a needfor improved devices and methods that will further allow more accuratepositioning of a prosthetic valve and that will also more securelyanchor the valve in place. In addition to needing improved devices,there is also a need for improved delivery systems and improved tools ordevices and methods for loading the devices onto their respectivedelivery systems. At least some of these objectives will be met by theexemplary embodiments disclosed herein.

SUMMARY OF THE INVENTION

The present invention generally relates to medical devices and methods,and more particularly relates to devices and methods for loading aprosthesis onto a delivery system. The prosthesis may be any device butin preferred embodiments is used to treat valve insufficiency, such asmitral insufficiency, also referred to as mitral regurgitation. Thedelivery system may be any system used to deliver the prosthesis eitherby traditional surgical implantation methods, or by less invasivepercutaneous catheter or minimally invasive transapical methods. Whilethe present disclosure focuses on fixtures for loading the prosthesisonto a delivery system, this is not intended to be limiting. Theprosthetic valves disclosed herein may also be used to treat other bodyvalves including other heart valves or venous valves. Exemplary heartvalves include the aortic valve, the triscupsid valve, or the pulmonaryvalve. The loading devices disclosed herein may be used to load anyprosthesis onto any delivery system.

In a first aspect of the present invention, a device for loading aprosthesis onto a delivery system comprises a first housing comprising afirst inlet, a first outlet, and a first central bore extendingtherebetween. The first housing has one or more actuators configured toactuate radially inward or outward, and the one or more actuators areadapted to selectively compress a discrete portion of the prosthesisradially inward when the prosthesis is disposed in the first centralbore and while adjacent portions of the prosthesis remain uncompressedby the one or more actuators.

The first central bore may comprise a constant diameter region or afirst tapered region adapted to radially collapse the prosthesis from afirst initial diameter to a smaller diameter when the prosthesis ispassed therethrough. The one or more actuators may comprise threeactuators circumferentially disposed around the first housing aboutevery 120 degrees. The one or more actuators may be operably coupledtogether such that they are actuated simultaneously. The device mayfurther comprise a collar that is threadably engaged with the firsthousing. Rotating the collar actuates the one or more actuators. The oneor more actuators may comprise spring loaded actuators biased to returnto a position disposed radially outward from the first central bore. Thefirst housing may further comprise a plurality of engagement elementsfor engaging an adjacent housing. The device may also include a supportelement that is releasably engaged with the first housing. The innersupport element may be configured to support an inner surface of theprosthesis.

The device may further comprise a second housing coupleable end-to-endwith the first housing. The second housing may comprise a second inlet,a second outlet, and a second central bore extending therebetween. Thesecond central bore may have a second tapered region that is adapted toradially collapse the prosthesis from a second initial diameter to asecond smaller diameter as the prosthesis is advanced through the secondcentral bore. The second central bore may further comprise a secondconstant diameter region in communication with the first central boreand proximal thereof. The second central bore may further comprise afilleted region disposed between the second tapered region and thesecond constant diameter region. The second central bore may be at leastpartially cylindrically shaped. The second housing may comprise aplurality of engagement elements for releasably engaging the secondhousing with an adjacent housing, or a plurality of engagementreceptacles for receiving engagement elements on an adjacent housing.The plurality of engagement elements may comprise three engagement tabsarranged circumferentially around the first housing approximately every120 degrees. Passage of the prosthesis through the second central boremay shape the prosthesis to have a circular cross-section.

The device may further comprise a third housing coupleable end-to-endwith the first or the second housing. The third housing may comprise athird inlet, a third outlet, and a third central bore extendingtherebetween and in communication with the first central bore or thesecond central bore. The third central bore may have a third taperedregion adapted to radially collapse the prosthesis from a third diameterto a diameter smaller than the third diameter as the prosthesis isadvanced through the third central bore. The third central bore mayfurther comprise a third constant diameter region in communication withthe third tapered region and distal thereto. The third central bore mayalso comprise a filleted region disposed between the third taperedregion and the third constant diameter region. The third central boremay be at least partially cylindrically shaped. The third housing maycomprise a plurality of engagement elements for releasably engaging anadjacent housing. The third housing may comprise a plurality ofengagement receptacles for receiving engagement elements on an adjacenthousing. The plurality of engagement elements may comprise threeengagement tabs arranged circumferentially around the first housingapproximately every 120 degrees. Passage of the prosthesis through thethird central bore may shape the prosthesis to have a circularcross-section.

The prosthesis may comprise a prosthetic heart valve, and may comprise aplurality of anchoring tabs, and wherein actuation of the one or moreactuators is adapted to move the plurality of anchoring tabs radiallyinward. The plurality of anchoring tabs may be adapted to be releasablyengaged with retaining features on the delivery catheter. The pluralityof anchoring tabs may comprise commissure posts on a prosthetic heartvalve.

In another aspect of the present invention, a system for loading aprosthesis onto a delivery system comprises the loading device describedabove in addition to a prosthetic heart valve and a delivery device.

In still another aspect of the present invention, a method for loading aprosthesis onto a delivery system comprises providing a prosthetic valvehaving a plurality of commissure posts coupled thereto, wherein theprosthetic valve comprises an unbiased diameter, and reducing theunbiased diameter of the prosthetic valve in selected discrete regions,the selected discrete regions comprising the commissure posts. Themethod also includes loading the reduced diameter prosthetic valve ontoa delivery device.

Reducing the unbiased diameter of the prosthetic valve may compriseactuating one or more actuators on a first housing, wherein the one ormore actuators may selectively engage discrete regions of the prostheticvalve. The method may further comprise passing the prosthetic valvethrough a constant diameter portion of a central channel in the firsthousing. Actuating the one or more actuators may comprise depressing oneor more pins or fingers radially inward to engage the discrete regionsof the prosthetic valve. The discrete regions may move radially inwardinto a reduced profile. Depressing may comprise simultaneouslydepressing the one or more pins or fingers.

The method may further comprise reducing diameter of the prostheticvalve from the unbiased diameter to a first diameter less than theunbiased diameter. Reducing diameter of the prosthetic valve from theunbiased diameter to the first diameter may comprise passing theprosthetic valve through a tapered central channel. Passing theprosthetic valve through the tapered central channel may comprisepushing or pulling the prosthetic valve therethrough. Passing theprosthetic valve through the tapered central channel may compriseshaping the prosthetic valve to have a circular cross-section.

The method may further comprise reducing diameter of the prostheticvalve from the first diameter to a second diameter less than the firstdiameter. Reducing diameter from the first diameter to the seconddiameter may comprise passing the prosthetic valve through a secondtapered central channel. Passing the prosthetic valve through the secondtapered central channel may comprise pushing or pulling the prostheticvalve therethrough.

The delivery device may comprise an inner shaft and an outer shaftslidably disposed thereover, and loading the reduced diameter prostheticvalve may comprise disposing the prosthetic valve between the innershaft and outer shafts. Loading the reduced diameter prosthetic valvemay comprise releasably engaging the commissure posts with the deliverydevice.

The prosthetic valve may be fabricated from a nickel titanium alloy, andthe method may further comprise cooling the prosthetic valve to atemperature less than or equal to the austenitic finish temperature ofthe prosthetic valve. Cooling the prosthetic valve may comprise coolingthe prosthetic valve in chilled saline. The diameter of the prostheticvalve may be reduced from the unbiased diameter to the first diameter ina first housing, and the diameter of the prosthetic valve may be reducedfrom the first diameter to the second diameter in a second housing, andthe method may further comprise coupling the first housing with thesecond housing. The first housing and the second housing may beuncoupled from one another after the diameter has been reduced to thefirst diameter. The method may also comprise supporting an inner surfaceof the prosthesis with a support element.

These and other embodiments are described in further detail in thefollowing description related to the appended drawing figures.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 is a schematic illustration of the left ventricle of a heartshowing blood flow during systole with arrows.

FIG. 2 is a schematic illustration of the left ventricle of a hearthaving prolapsed leaflets in the mitral valve.

FIG. 3 is a schematic illustration of a heart in a patient sufferingfrom cardiomyopathy where the heart is dilated and the leaflets do notmeet.

FIG. 3A shows normal closure of the valve leaflets.

FIG. 3B shows abnormal closure of the valve leaflets.

FIG. 4 illustrates mitral valve regurgitation in the left ventricle of aheart having impaired papillary muscles.

FIGS. 5A-5B illustrate anatomy of the mitral valve.

FIG. 6 illustrates an exemplary embodiment of an uncovered frame in aprosthetic cardiac valve, with the frame flattened out and unrolled.

FIG. 7 illustrates another exemplary embodiment of an uncovered frame ina prosthetic cardiac valve, with the frame flattened out and unrolled.

FIG. 8 illustrates still another exemplary embodiment of an uncoveredframe in a prosthetic cardiac valve, with the frame flattened out andunrolled.

FIG. 9A illustrates a perspective view of an uncovered frame in aprosthetic cardiac valve after it has expanded.

FIG. 9B illustrates a top view of the embodiment in FIG. 9A.

FIG. 10 illustrates the frame of FIG. 9A with the covering therebyforming a prosthetic cardiac valve.

FIGS. 11A-11D illustrate an exemplary embodiment of a delivery systemused to transapically deliver a prosthetic cardiac valve.

FIGS. 12A-12L illustrate an exemplary method of implanting a prostheticcardiac valve.

FIGS. 13A-13L illustrate another exemplary method of implanting aprosthetic cardiac valve.

FIG. 14 is a perspective view of an exemplary loading system for theloading of a prosthetic valve with commissures into a delivery system.

FIG. 15 is a side view of the loading system in FIG. 14.

FIG. 16 cross-sectional view of the loading system in FIG. 14.

FIG. 17 is a partially exploded side view of the loading system in FIG.14.

FIG. 18A is an end view of the loading system in FIG. 14 in anunactuated configuration.

FIG. 18B is and end view of the loading system in FIG. 14 in an actuatedconfiguration.

FIG. 19 is a partial cross-sectional view of a prosthesis withcommissures being inserted into the first stage of the loading system ofFIG. 14.

FIG. 20 is a partial cross-sectional view the prosthesis in FIG. 19travelling from the first to the second stage of the loading system ofFIG. 14.

FIG. 21 is a partial cross-sectional view of the prosthesis in FIG. 19travelling through the second stage of the loading system of FIG. 14.

FIG. 22 is a partial cross-sectional view of the prosthesis in FIG. 19travelling from the second to the third stage of the loading system inFIG. 14.

FIG. 23 is a partial cross-sectional view of the prosthesis in FIG. 19positioned within the third stage of the loading system of FIG. 14.

FIG. 24 is a partial cross-sectional view of the prosthesis in FIG. 19positioned in the third stage of the loading system of FIG. 14 and witha delivery system also engaged with the loading system.

FIG. 25 is a partial cross-sectional view of the prosthesis in FIG. 19after actuation of the loading system of FIG. 14.

FIG. 26A is an end view of the loading system in FIG. 14 showing aprosthesis in a collapsed but undeflected configuration.

FIG. 26B is an end view of the loading system in FIG. 14 with aprosthesis in a collapsed and deflected configuration.

FIG. 27 illustrates another exemplary embodiment of a loading system.

FIGS. 28A-28B illustrate the loading system of FIG. 27 prior toactuation.

FIGS. 29A-29B illustrate the loading system of FIG. 27 after actuation.

FIGS. 30-33 illustrate still another exemplary embodiment of a loadingsystem.

DETAILED DESCRIPTION OF THE INVENTION

Specific embodiments of the disclosed device, delivery system, andmethod will now be described with reference to the drawings. Nothing inthis detailed description is intended to imply that any particularcomponent, feature, or step is essential to the invention.

Cardiac Anatomy. The left ventricle LV of a normal heart H in systole isillustrated in FIG. 1. The left ventricle LV is contracting and bloodflows outwardly through the aortic valve AV, a tricuspid valve in thedirection of the arrows. Back flow of blood or “regurgitation” throughthe mitral valve MV is prevented since the mitral valve is configured asa “check valve” which prevents back flow when pressure in the leftventricle is higher than that in the left atrium LA. The mitral valve MVcomprises a pair of leaflets having free edges FE which meet evenly toclose, as illustrated in FIG. 1. The opposite ends of the leaflets LFare attached to the surrounding heart structure along an annular regionreferred to as the annulus AN. The free edges FE of the leaflets LF aresecured to the lower portions of the left ventricle LV through chordaetendineae CT (also referred to herein as the chordae) which include aplurality of branching tendons secured over the lower surfaces of eachof the valve leaflets LF. The chordae CT in turn, are attached to thepapillary muscles PM which extend upwardly from the lower portions ofthe left ventricle and interventricular septum IVS.

Referring now to FIGS. 2-4, a number of structural defects in the heartcan cause mitral valve regurgitation. Ruptured chordae RCT, as shown inFIG. 2, can cause a valve leaflet LF2 to prolapse since inadequatetension is transmitted to the leaflet via the chordae. While the otherleaflet LF1 maintains a normal profile, the two valve leaflets do notproperly meet and leakage from the left ventricle LV into the leftatrium LA will occur, as shown by the arrow.

Regurgitation also occurs in the patients suffering from cardiomyopathywhere the heart is dilated and the increased size prevents the valveleaflets LF from meeting properly, as shown in FIG. 3. The enlargementof the heart causes the mitral annulus to become enlarged, making itimpossible for the free edges FE to meet during systole. The free edgesof the anterior and posterior leaflets normally meet along a line ofcoaptation C as shown in FIG. 3A, but a significant gap G can be left inpatients suffering from cardiomyopathy, as shown in FIG. 3B.

Mitral valve regurgitation can also occur in patients who have sufferedischemic heart disease where the functioning of the papillary muscles PMis impaired, as illustrated in FIG. 4. As the left ventricle LVcontracts during systole, the papillary muscles PM do not contractsufficiently to effect proper closure. The leaflets LF1 and LF2 thenprolapse, as illustrated. Leakage again occurs from the left ventricleLV to the left atrium LA, as shown by the arrow.

FIG. 5A more clearly illustrates the anatomy of a mitral valve MV whichis a bicuspid valve having an anterior side ANT and a posterior sidePOST. The valve includes an anterior (aortic) leaflet AL and a posterior(mural) leaflet PL. Chordae tendineae CT couple the valve leaflets AL.PL with the antero-lateral papillary muscle ALPM and the postero-medialpapillary muscle PMPM. The valve leaflets AL, PL join one another alonga line referred to as the antero-lateral commissure ALC and theposterior-medial commissure PMC. The annulus AN circumscribes the valveleaflets, and two regions adjacent an anterior portion of the annulus,on opposite sides of the anterior leaflet are referred to as the leftfibrous trigone LFT and also the right fibrous trigone RFT. These areasare indicted generally by the solid triangles. FIG. 5B more clearlyillustrates the left and right fibrous trigones. LFT, RFT.

While various surgical techniques as well as implantable devices havebeen proposed and appear to be promising treatments for mitralregurgitation, surgical approaches can require a lengthy recoveryperiod, and implantable devices have varying clinical results.Therefore, there still is a need for improved devices, delivery systems,loading fixtures, and methods for treating mitral regurgitation. Whilethe embodiments disclosed herein are directed to an implantableprosthetic mitral valve for treating mitral regurgitation, one of skillin the art will appreciate that this is not intended to be limiting, andthe devices and methods disclosed herein may also be used to treat othercardiac valves such as the tricuspid valve, aortic valve, pulmonaryvalve, etc, as well as other valves in the body such as venous valves.

Prosthetic Valve. Prosthetic valves have been surgically implanted inthe heart as a treatment for mitral regurgitation. Some of these valveshave been valves harvested from animals such as porcine valves, andothers have been prosthetic mechanical valves with or without a tissuecovering. More recently, minimally invasive catheter technology has beenused to deliver prosthetic valves to the heart. These valves typicallyinclude an anchor for securing the valve to the patient's heart, and avalve mechanism, either a mechanical valve, a valve with animal tissue,or combinations thereof. The prosthetic valve once implanted, takes overfor malfunctioning native valve, thereby reducing or eliminating valvarinsufficiency. While some of these valves appear promising, there stillis a need for improved valves. Positioning and anchoring the prostheticvalve in the native anatomy remains a challenge. The following disclosesexemplary embodiments of a prosthetic valve, a delivery system for theprosthetic valve, and methods of delivering the valve that overcome someof the challenges associated with existing prosthetic valves.

FIG. 6 illustrates an exemplary embodiment of a prosthetic cardiac valvein the collapsed configuration. Coverings from the frame (e.g. fabric ortissue) has been removed to permit observation of the underlying frame600. The frame has been unrolled and flattened out. The prosthetic valveframe 600 has an atrial region 606, an annular region 608, and aventricular region 610. The frame 600 is formed from a plurality ofinterconnected struts that form a series of peaks and valleys which canexpand and contract relative to one another thereby permitting the frameto be loaded onto a delivery catheter in a collapsed configuration, andthen radially expanded at a target treatment site for implantation.Preferred embodiments are self-expanding and may be fabricated usingsuperelastic nitinol or other self-expanding materials. Shape memoryalloys that spring open above a transition temperature may also be used,and expandable members may also be used to expand the frame when plasticdeformation (e.g. balloon expansion) is required to open the frame.

Atrial region 606 has a skirt 616 which includes a plurality ofinterconnected struts that form a series of peaks and valleys. In thisregion, the struts are skew relative to one another and thus theresulting cell pattern has an enlarged end and the opposite end tapersto a smaller end. In preferred embodiments, the anterior portion of theatrial skirt does not have a flanged region like the posterior portion,thus the anterior portion 602 of the atrial region may have shorterstruts than the posterior region 604. Thus the peaks and valleys in theanterior portion are axially offset from those in the remainingposterior portion of the atrial region. This may be advantageous as itprevents the struts in the anterior portion of the atrial skirt fromprotruding upwards potentially impinging against the left atrium andcausing perforations. Additionally, the shortened struts and offsetpeaks and valleys form an alignment element 614 that can assist thephysician visualize delivery of the prosthetic valve to the mitral valveand alignment of the prosthetic valve prior to expansion of theprosthetic valve. Optional radiopaque markers 614 a are disposed oneither side of the offset peaks and valleys and further help withvisualization during implantation of the valve. The atrial regionpreferably self-expands to either a cylindrical shape, or it may have aD-shaped cross-section where the anterior portion 602 is substantiallyflat, and the posterior portion 604 is cylindrically shaped. This allowsthe atrial skirt to conform to the anatomy of the native mitral valve,thereby preventing obstruction of the left ventricular outflow tract.Additionally, the atrial skirt may also be formed so that uponexpansion, the skirt flares outward and forms a flange that can restagainst a superior surface of the mitral valve. The flanged region ispreferably along the posterior portion of the atrial skirt, and theanterior portion of the atrial skirt remains flangeless. Or, the flangemay extend entirely around the atrial skirt. The atrial region isconnected to the adjacent annular region 608 with connecting strutswhich are preferably linear and substantially parallel to thelongitudinal axis of the frame.

The annular region 608 is also comprised of a plurality of axiallyoriented and interconnected struts that form peaks and valleys thatallow radial expansion. The struts are preferably parallel with oneanother and parallel with the longitudinal axis of the frame. Theannular region may also be self-expanding and expand into a cylindricalshape, or more preferably the annular region may expand to have aD-shaped cross-section as described above with respect to the atrialregion. Thus, the annular region may similarly have a flat anteriorportion, and a cylindrically shaped posterior portion. Upon delivery,the annular region is aligned with and expanded into engagement with themitral valve annulus. Connector struts join the annular region with theventricular region 610.

The ventricular region 610 also includes a plurality of interconnectedstruts that form peaks and valleys. Additionally, the struts in theventricular region form the leaflet commissures 613 which are coveredwith fabric, pericardial tissue, or other materials to form theprosthetic valve leaflets. Holes in the commissures allow suture to beattached thereto. Struts in the ventricular region also form aventricular skirt 628 which expands outward to engage the anterior andposterior mitral valve leaflets, and struts in the ventricular regionalso form the anterior tabs 624 and the posterior tab 630. The anteriortabs are designed to capture the anterior mitral valve leaflet betweenan inner surface of the anterior tab and outer surface of theventricular skirt. Any adjacent chordae tendineae may also be capturedtherebetween. Also, the tip of the anterior tab engages the fibroustrigone on an anterior portion of the mitral valve, one on the left andone on the right side. The posterior tab similarly captures theposterior mitral valve leaflet between an inner surface of the posteriortab and an outer surface of the ventricular skirt, along with anyadjacent chordae tendineae. This will be described in more detail below.

By controlling strut length or axial position of the anterior orposterior tabs along the frame, deployment of the tabs may becontrolled. Thus in this exemplary embodiment, because the length of thestruts in the anterior tabs and posterior tabs 624, 630 as well as theirrelative position along the frame are the same as one another, when aconstraining sheath is retracted away from the tabs, the anterior andposterior tabs will partially spring outward together. As theconstraining sheath is further retracted, the remainder of the anteriortabs will self-expand radially outward. Further retraction of theconstraining sheath then allows the remainder of the posterior tab tofinish its radial expansion, and finally the ventricular skirt willradially expand outward. While strut lengths and axial position of theposterior tab and the ventricular skirt are similar, internal strutsconnect the ventricular skirt with the commissures, and this delaysexpansion of the ventricular skirt slightly, thus the posterior tabfinishes expansion before the ventricular skirt. Using this sequence ofdeploying the prosthetic valve may allow the valve to more accuratelydelivered and also more securely anchored into position.

Suture holes 621 are disposed along the struts of the annular region aswell as the ventricular region to allow attachment of a cover such aspericardium or a polymer such as Dacron or ePTFE. The suture holes mayalso be disposed along any other part of the frame. Barbs 623 aredisposed along the ventricular skirt 628 to help anchor the prostheticvalve to adjacent tissue. Commissure tabs or tabs 612 are disposed onthe tips of the commissures 613 and may be used to releasably couple thecommissures with a delivery system as will be described below. Thisallows the frame to expand first, and then the commissures may bereleased from the delivery system afterwards. One of skill in the artwill appreciate that a number of strut geometries may be used, andadditionally that strut dimensions such as length, width, thickness,etc. may be adjusted in order to provide the anchor with the desiredmechanical properties such as stiffness, radial crush strength,commissure deflection, etc. Therefore, the illustrated geometry is notintended to be limiting.

The frame may be formed by EDM, laser cutting, photochemical etching, orother techniques known in the art. Hypodermic tubing or flat sheets maybe used to form the frame. Once the frame has been cut and formed into acylinder, it may be radially expanded into a desired geometry and heattreated using known processes to set the shape. Thus, the prostheticvalve may be loaded onto a delivery catheter in a collapsedconfiguration and constrained in the collapsed configuration with aconstraining sheath. Removal of the constraining sheath will allow theanchor to self-expand into its unbiased pre-set shape. In otherembodiments, an expandable member such as a balloon may be used toradially expand the anchor into its preferred expanded configuration.

FIG. 7 illustrates another exemplary embodiment of a prosthetic cardiacvalve in the collapsed configuration, and similar to the previousembodiment with the major difference being the strut lengths in theanterior tabs, posterior tab, and ventricular skirt. Varying the strutlengths allow the sequence of expansion of the anterior and posteriortabs and ventricular skirt to be controlled. Coverings from the frame(e.g. fabric or tissue) has been removed to permit observation of theunderlying frame 700. The frame has been unrolled and flattened out. Theprosthetic valve frame 700 has an atrial region 706, an annular region708, and a ventricular region 710. The frame 700 is formed from aplurality of interconnected struts that form a series of peaks andvalleys which can expand and contract relative to one another therebypermitting the frame to be loaded onto a delivery catheter in acollapsed configuration, and then radially expanded at a targettreatment site for implantation. Preferred embodiments areself-expanding and may be fabricated using superelastic nitinol or otherself-expanding materials. Shape memory alloys that spring open above atransition temperature may also be used, and expandable members may alsobe used to expand the frame when plastic deformation (e.g. balloonexpansion) is required to open the frame.

Atrial region 706 has a skirt 716 which includes a plurality ofinterconnected struts that form a series of peaks and valleys. In thisregion, the struts are skew relative to one another and thus theresulting cell pattern has an enlarged end and the opposite end tapersto a smaller end. An anterior portion 702 of the atrial region hasshorter struts than the posterior region 704. Thus the peaks and valleysin the anterior portion are axially offset from those in the remainingposterior portion of the atrial region. This allows creation of analignment element 714 to help the physician deliver the prosthetic valveto the mitral valve and align the prosthetic valve prior to expansion ofthe prosthetic valve. Other aspects of the atrial region 706 are similarto those of the atrial region 606 in FIG. 6. Optional radiopaque markers714 a are disposed on either side of the offset peaks and valleys andhelp with visualization during implantation of the valve. The atrialregion preferably self-expands to either a cylindrical shape, or it mayhave a D-shaped cross-section where the anterior portion 702 issubstantially flat, and the posterior portion 704 is cylindricallyshaped. This allows the atrial skirt to conform to the anatomy of thenative mitral valve, thereby preventing obstruction of the leftventricular outflow tract. Additionally, the atrial skirt may also beformed so that upon expansion, the skirt flares outward and forms aflange that can rest against a superior surface of the mitral valve. Theflanged region is preferably along the posterior portion of the atrialskirt, and the anterior portion of the atrial skirt remains flangeless.Or, the flange may extend entirely around the atrial skirt. The atrialregion is connected to the adjacent annular region 708 with connectingstruts which are preferably linear and substantially parallel to thelongitudinal axis of the frame.

The annular region 708 is also comprised of a plurality of axiallyoriented and interconnected struts that form peaks and valleys thatallow radial expansion. The struts are preferably parallel with oneanother and parallel with the longitudinal axis of the frame. Theannular region may also be self-expanding and expand into a cylindricalshape, or more preferably the annular region may expand to have aD-shaped cross-section as described above with respect to the atrialregion. Thus, the annular region may similarly have a flat anteriorportion, and a cylindrically shaped posterior portion. Upon delivery,the annular region is aligned with and expanded into engagement with themitral valve annulus. Connector struts join the annular region with theventricular region 710.

The ventricular region 710 also includes a plurality of interconnectedstruts that form peaks and valleys. Additionally, the struts in theventricular region form the leaflet commissures 713 which are coveredwith fabric, pericardial tissue, or other materials to form theprosthetic valve leaflets. Holes in the commissures allow suture to beattached thereto. Struts in the ventricular region also form aventricular skirt 728 which expands outward to engage the anterior andposterior mitral valve leaflets, and struts in the ventricular regionalso form the anterior tabs 724 and the posterior tab 730. The anteriortabs are designed to capture the anterior mitral valve leaflet betweenan inner surface of the anterior tab and outer surface of theventricular skirt. Any adjacent chordae tendineae may also be capturedtherebetween. Also, the tip of the anterior tab engages the fibroustrigone on an anterior portion of the mitral valve, one on the left andone on the right side. The posterior tab similarly captures theposterior mitral valve leaflet between an inner surface of the posteriortab and an outer surface of the ventricular skirt, along with anyadjacent chordae tendineae. This will be described in more detail below.

By controlling strut length or axial position of the anterior orposterior tabs along the frame, deployment of the tabs may becontrolled. Thus in this exemplary embodiment, because the length of thestruts in the anterior tabs and posterior tabs 724, 730 as well as theirrelative position along the frame are the same as one another, when aconstraining sheath is retracted away from the tabs, the anterior andposterior tabs will partially spring outward together. As theconstraining sheath is further retracted, the remainder of the anteriortabs will self-expand radially outward because they are the shortestrelative to the struts in the ventricular skirt and the posterior tab.Further retraction of the constraining sheath then allows theventricular skirt to radially expand, and finally further retraction ofthe sheath allows the remainder of the posterior tab to finish it'sradial expansion. Using this sequence of deploying the prosthetic valvemay allow the valve to more accurately be delivered and also moresecurely anchored into position.

Suture holes 721 are disposed along the struts of the annular region aswell as the ventricular region to allow attachment of a cover such aspericardium or a polymer such as Dacron or ePTFE. The suture holes mayalso be disposed along any other part of the frame. Barbs 723 aredisposed along the ventricular skirt 728 to help anchor the prostheticvalve to adjacent tissue. Commissure tabs or tabs 712 are disposed onthe tips of the commissures 713 and may be used to releasably couple thecommissures with a delivery system as will be described below. Thisallows the frame to expand first, and then the commissures may bereleased from the delivery system afterwards. One of skill in the artwill appreciate that a number of strut geometries may be used, andadditionally that strut dimensions such as length, width, thickness,etc. may be adjusted in order to provide the anchor with the desiredmechanical properties such as stiffness, radial crush strength,commissure deflection, etc. Therefore, the illustrated geometry is notintended to be limiting. The frame may be formed similarly as describedabove with respect to FIG. 6.

FIG. 8 illustrates another exemplary embodiment of a prosthetic cardiacvalve in the collapsed configuration, and is similar to the previousembodiments, with the major difference being that the posterior tab isdesigned to expand to form an elongate horizontal section which allowsengagement and anchoring of the posterior tab with the sub-annularregion between the posterior leaflet and the ventricular wall. Thus, theelongate horizontal section contacts a larger region of the sub-annularregion as compared with a posterior tab that only has a tapered tipformed from a single hinge between struts. This provides enhancedanchoring of the prosthetic valve. In this exemplary embodiment, theanterior tabs will completely self-expand first, followed by theposterior tab and then the ventricular skirt. However, in somesituations external factors such as the delivery system, anatomy, etc.may alter the sequence of expansion, and therefore this is not intendedto be limiting. Coverings from the frame (e.g. fabric or tissue) havebeen removed to permit observation of the underlying frame 800. Theframe has been unrolled and flattened out. The prosthetic valve frame800 has an atrial region 806, an annular region 808, and a ventricularregion 810. The frame 800 is formed from a plurality of interconnectedstruts that form a series of peaks and valleys which can expand andcontract relative to one another thereby permitting the frame to beloaded onto a delivery catheter in a collapsed configuration, and thenradially expanded at a target treatment site for implantation. Preferredembodiments are self-expanding and may be fabricated using superelasticnitinol or other self-expanding materials. Shape memory alloys thatspring open above a transition temperature may also be used, andexpandable members may also be used to expand the frame when plasticdeformation (e.g. balloon expansion) is required to open the frame.

Atrial region 806 has a skirt 816 which includes a plurality ofinterconnected struts that form a series of peaks and valleys. In thisregion, the struts are skew relative to one another and thus theresulting cell pattern has an enlarged end and the opposite end tapersto a smaller end. An anterior portion 802 of the atrial region hasshorter struts than the posterior region 804. Thus the peaks and valleysin the anterior portion are axially offset from those in the remainingposterior portion of the atrial region. This allows creation of analignment element 814 to help the physician deliver the prosthetic valveto the mitral valve and align the prosthetic valve prior to expansion ofthe prosthetic valve. Other aspects of the atrial region 806 are similarto those of the atrial region 606 in FIG. 6. Optional radiopaque markers814 a are disposed on either side of the offset peaks and valleys andhelp with visualization during implantation of the valve. The atrialregion preferably self-expands to either a cylindrical shape, or it mayhave a D-shaped cross-section where the anterior portion 802 issubstantially flat, and the posterior portion 804 is cylindricallyshaped. This allows the atrial skirt to conform to the anatomy of thenative mitral valve, thereby preventing obstruction of the leftventricular outflow tract. Additionally, the atrial skirt may also beformed so that upon expansion, the skirt flares outward and forms aflange that can rest against a superior surface of the mitral valve. Theflanged region is preferably along the posterior portion of the atrialskirt, and the anterior portion of the atrial skirt remains flangeless.Or, the flange may extend entirely around the atrial skirt. The atrialregion is connected to the adjacent annular region 808 with connectingstruts which are preferably linear and substantially parallel to thelongitudinal axis of the frame.

The annular region 808 is also comprised of a plurality of axiallyoriented and interconnected struts that form peaks and valleys thatallow radial expansion. The struts are preferably parallel with oneanother and parallel with the longitudinal axis of the frame. Theannular region may also be self-expanding and expand into a cylindricalshape, or more preferably the annular region may expand to have aD-shaped cross-section as described above with respect to the atrialregion. Thus, the annular region may similarly have a flat anteriorportion, and a cylindrically shaped posterior portion. Upon delivery,the annular region is aligned with and expanded into engagement with themitral valve annulus. Connector struts join the annular region with theventricular region 810.

The ventricular region 810 also includes a plurality of interconnectedstruts that form peaks and valleys. Additionally, the struts in theventricular region form the leaflet commissures 813 which are coveredwith fabric, pericardial tissue, or other materials to form theprosthetic valve leaflets. Holes in the commissures allow suture to beattached thereto. Struts in the ventricular region also form aventricular skirt 828 which expands outward to engage the anterior andposterior mitral valve leaflets, and struts in the ventricular regionalso form the anterior tabs 824 and the posterior tab 830. The anteriortabs are designed to capture the anterior mitral valve leaflet betweenan inner surface of the anterior tab and outer surface of theventricular skirt. Any adjacent chordae tendineae may also be capturedtherebetween. Also, the tip of the anterior tab engages the fibroustrigone on an anterior portion of the mitral valve, one on the left andone on the right side. The posterior tab similarly captures theposterior mitral valve leaflet between an inner surface of the posteriortab and an outer surface of the ventricular skirt, along with anyadjacent chordae tendineae. This will be described in more detail below.The posterior tab is similar to the posterior tabs described above inFIGS. 6-7, except that in this embodiment, the posterior tab comprisesfour interconnected struts as opposed to two interconnected struts.Thus, in this embodiment the plurality of interconnected struts formthree hinged regions 836 along the tab. Upon expansion of the posteriortab, the hinged regions will also expand, thereby forming an elongatehorizontal section which allows engagement and anchoring of theposterior tab with the sub-annular region between the posterior leafletand the ventricular wall. This may help position and anchor theprosthetic valve better than posterior tabs which only have a smallerfootprint or a single tapered tip for engagement with the posteriorportion of the mitral valve. The posterior leaflet in this embodiment,may be substituted with any of the other posterior tabs described inthis specification.

By controlling strut length or axial position of the anterior orposterior tabs along the frame, deployment of the tabs may becontrolled. Thus in this exemplary embodiment, because the length of thestruts in the anterior tabs and posterior tabs 824, 830 as well as theirrelative position along the frame are the same as one another, when aconstraining sheath is retracted away from the tabs, the anterior andposterior tabs will partially spring outward together. As theconstraining sheath is further retracted, the remainder of the anteriortabs will self-expand radially outward because they are the shortestrelative to the struts in the ventricular skirt and the posterior tab.Further retraction of the constraining sheath then allows the remainderof the posterior tab to finish self-expanding, followed byself-expansion of the ventricular skirt. Using this sequence ofdeploying the prosthetic valve may allow the valve to more accurately bedelivered and also more securely anchored into position.

Suture holes 821 are disposed along the struts of the annular region aswell as the ventricular region to allow attachment of a cover such aspericardium or a polymer such as Dacron or ePTFE. The suture holes mayalso be disposed along any other part of the frame. Barbs 823 aredisposed along the ventricular skirt 828 to help anchor the prostheticvalve to adjacent tissue. Commissure tabs or tabs 812 are disposed onthe tips of the commissures 813 and may be used to releasably couple thecommissures with a delivery system as will be described below. Thisallows the frame to expand first, and then the commissures may bereleased from the delivery system afterwards. One of skill in the artwill appreciate that a number of strut geometries may be used, andadditionally that strut dimensions such as length, width, thickness,etc. may be adjusted in order to provide the anchor with the desiredmechanical properties such as stiffness, radial crush strength,commissure deflection, etc. Therefore, the illustrated geometry is notintended to be limiting. The frame may be formed similarly as describedabove with respect to those previously described above.

FIG. 9A illustrates the frame 900 of a prosthetic cardiac valve after ithas expanded. Any of the frame embodiments described above may take thisform as each of the above frames have similar geometry but they expandin different order. The frame includes the atrial skirt 906 withanterior portion 914 and posterior portion 916. A flanged region isformed around the posterior portion and the anterior portion remainsflangeless. Additionally, the anterior portion is generally flat, whilethe posterior portion is cylindrically shaped, thereby forming aD-shaped cross-section which accommodates the mitral valve anatomy. FIG.9B is a top view of the embodiment in FIG. 9A and more clearlyillustrates the D-shaped cross-section.

The frame also includes the annular region 910 and ventricular skirt912. Anterior tabs 904 (only one visible in this view) is fully expandedsuch that a space exists between the inner surface of the anterior taband and outer surface of the ventricular skirt. This allows the anteriorleaflet and adjacent chordae to be captured therebetween. Similarly, theposterior tab 902 is also fully deployed, with a similar space betweenthe inner surface of the posterior tab 902 and an outer surface of theventricular skirt. This allows the posterior leaflet and adjacentchordae tendineae to be captured therebetween. The commissure posts 908are also visible and are disposed in the inner channel formed by theframe. The commissure posts are used to form the prosthetic mitral valveleaflets. The overall shape of the expanded frame is D-shaped, with theanterior portion flat and the posterior portion cylindrically shaped.

FIG. 10 illustrates the expanded frame covered with a cover 1002 such aspericardial tissue or a polymer such as ePTFE or a fabric like Dacronattached to the frame, thereby forming the prosthetic cardiac valve1000. The atrial skirt may be entirely covered by a material, or inpreferred embodiments, the covering is only disposed between adjacentstruts 1012 in adjacent cells in the flanged portion of the atrialskirt. The area 1014 between adjacent struts within the same cell remainuncovered. This allows blood flow to remain substantially uninterruptedwhile the prosthetic valve is being implanted. Suture 1010 may be usedto attach the cover to the frame. In this view, only the posterior tab1006 is visible on the posterior portion of the prosthetic valve alongwith ventricular skirt 1008 and atrial skirt 1004.

Delivery System. FIGS. 11A-11D illustrate an exemplary embodiment of adelivery system that may be used to deliver any of the prostheticcardiac valves disclosed in this specification. While the deliverysystem is designed to preferably deliver the prosthetic cardiac valvetransapically, one of skill in the art will appreciate that it may alsobe modified so that the prosthetic valve may be delivered via a cathetertransluminally, such using a transseptal route. One of skill in the artwill appreciate that using a transseptal route may require the relativemotion of the various shafts to be modified in order to accommodate theposition of the delivery system relative to the mitral valve.

FIG. 11A illustrates a perspective view of delivery system 1100. Thedelivery system 1100 includes a handle 1112 near a proximal end of thedelivery system and a distal tissue penetrating tip 1110. Four elongateshafts are included in the delivery system and include an outer sheathcatheter shaft 1102, a bell catheter shaft 1104 which is slidablydisposed in the outer sheath catheter shaft 1102, a hub catheter shaft1106 which remains stationary relative to the other shafts, but the bellcatheter shaft slides relative to the hub shaft, and finally an innerguidewire catheter shaft 1108 which is also fixed relative to the othershafts and has a lumen sized to receive a guidewire which passestherethrough and exits the distal tissue penetrating tip. An actuatormechanism 1114 is used to control movement of the various shafts as willbe explained in greater detail below, and flush lines 1116, 1118 withluer connectors are used to flush the annular regions between adjacentshafts. Flush line 1118 is used to flush the annular space between theouter sheath catheter shaft 1102 and the bell catheter shaft 1104. Flushline 1116 is used to flush the annular space between the bell catheter1104 and the hub catheter 1106. The inner guidewire catheter shaft 1108is stationary relative to the hub catheter 1106 therefore the annularspace may be sealed with an o-ring or other material. Luer connector1122 allows flushing of the guidewire lumen and a hemostatic valve suchas a Tuohy-Borst may be coupled to the luer connector to allow aguidewire to be advanced through the guidewire catheter shaft whilemaintaining hemostasis. Screws 1120 keep the handle housing coupledtogether. FIG. 11B illustrates a sideview of the delivery system 1100.

FIG. 11C is a partial exploded view of the delivery system 1100 and moreclearly illustrates the components in the handle 1112 and how theyinteract. The handle 1112 includes a housing having two halves 1112 a,1112 b which hold all the components. The handle is preferably heldtogether with screws 1120 and nuts 1120 b, although it may also besealed using other techniques such as a press fit, snap fit, adhesivebonding, ultrasonic welding, etc. Rotation of actuator wheel 1114 istranslated into linear motion of threaded insert 1124. The outer sheathcatheter shaft 1102 is coupled to the threaded insert 1124, thereforerotation of actuator wheel 1114 in one direction will advance the sheathcatheter shaft 1102, and rotation in the opposite direction will retractthe sheath catheter shaft 1102. Further rotation of actuator wheel 1114retracts threaded insert 1124 enough to bump into pins 1126 which arecoupled to insert 1128, thereby also moving insert 1128. The bellcatheter shaft 1106 is coupled to insert 1128, therefore furtherrotation of the actuator wheel 1114 will move the outer shaft 1102 andalso move the bell catheter shaft 1106. Rotation of the actuator wheelin the opposite direction advances the sheath and threaded insert 1124disengages from pins 1126. Spring 1130 returns insert 1128 to itsunbiased position, thereby returning the bell catheter shaft to itsunbiased position.

Any of the prosthetic cardiac valves disclosed herein may be carried bydelivery system 1100. The atrial skirt, annular skirt, anterior tabs,posterior tab and ventricular skirt are loaded over the bell cathetershaft and disposed under the outer sheath catheter shaft 1102. Theventricular skirt is loaded proximally so that it is closest to thehandle 1112 and the atrial skirt is loaded most distally so it isclosest to the tip 1110. Therefore, retraction of outer sheath cathetershaft 1102 plays a significant part in controlling deployment of theprosthetic cardiac valve. The atrial skirt therefore expands first whenthe outer sheath catheter is retracted. The prosthetic valve commissuresmay be coupled with a hub 1106 a on the distal portion of hub catheter1106 and then the bell catheter shaft is disposed thereover, therebyreleasably engaging the commissures with the delivery catheter. Onceother portions of the prosthetic cardiac valve have expanded, thecommissures may be released.

FIG. 11D highlights the distal portion of the delivery system 1100.Outer sheath catheter shaft 1102 advances and retracts relative to bellcatheter shaft 1104 which is slidably disposed in the outer sheathcatheter shaft 1102. Hub catheter shaft 1106 is shown slidably disposedin bell catheter shaft 1104 and with bell catheter shaft 1104 retractedso as to expose the hub 1106 a having slots 1106 b that hold theprosthetic valve commissures. Inner guidewire catheter shaft 1108 is theinnermost shaft and has a tapered conical section 1130 which provides asmooth transition for the prosthetic valve and prevents unwanted bendingor buckling of the prosthetic cardiac valve frame. Tissue penetratingtip 1110 is adapted to penetrate tissue, especially in a cardiactransapical procedure.

Loading Fixture. The prosthetic valve may be loaded manually by aphysician onto the delivery system, but this can be challenging sincethe valve must be properly oriented relative to the delivery system andthen the commissure posts must also be engaged with the slots orreceptacles on the delivery system, and captured therein. This mayrequire multiple operators to simultaneously manipulate the prosthesisas well as the delivery system and its actuator mechanisms. Therefore,it would be advantageous to provide a fixture to facilitate loading ofthe prosthetic valve onto the delivery system. FIGS. 14-18B illustratean exemplary embodiment of a loading fixture (also referred to herein asa loading device) that may be used to couple a prosthesis such as aprosthetic valve with a delivery system. The prosthesis may be anyprosthesis including the prosthetic valve described in this disclosure.Similarly, the delivery system may be any delivery system, includingthose described herein.

FIG. 14 illustrates the loading device 1401 having a body 1438 whichincludes three interlocking stages or housings including a first housing1405 (also referred to herein as the A stage or A housing), secondhousing 1407 (also referred to herein as the B stage or B housing), andthird housing 1409 (also referred to herein as the C stage or Chousing). The loading device 1401 allows a prosthesis such as aprosthetic valve to be inserted into one end of the loading device andas the prosthesis is passed therethrough, its overall diameter isreduced and selected regions of the prosthesis are further compressedradially inward when the loading device is actuated. This allowsengagement of the prosthesis with the delivery system prior to delivery.

An internal channel 1439 begins at the first housing 1405 with an inletorifice 1402 and terminates at the third housing 1409 at an outletorifice 1403. Three hand operated and spring loaded actuators 1404 arelocated in the third housing 1409 and are used to depress certainportions of a prosthesis such as a prosthetic heart valve in order toload the valve onto a delivery system, the details of which aredescribed in greater detail below.

As can be seen in FIG. 15, A stage 1405 includes a fitment ring 1406which provides a number of cantilevered tabs 1415 that are used to matewith a locking window 1416 of the subsequent stage by virtue of a snapfit 1417. Each fitment ring 1406 is fastened to a respective stage withthreaded fasteners 1414. By depressing the cantilevered tabs 1415, thesnap fit 1417 is released from the locking window 1416 and therespective stages (1405, 1407, or 1409) may be separated so that eachstage of the device can be manipulated individually.

FIG. 16 shows a cross-sectional view of the loading system 1401 shown inFIG. 15. In order to begin compression of a prosthetic heart valve, theA stage 1405 first has an internally tapered section 1426 which by wayof a filleted transition zone 1439 is coupled with a flat section 1428of constant diameter. Passing through the A stage 1405 has the effect ofreducing a prosthetic heart valve diameter from a first larger inputvalue to a second smaller output value, and also helps to shape-set theframe or scaffold portion of the valve into having a circular crosssection. The B stage 1407 first has an internally tapered section 1427which by way of a filleted transition zone 1440 is coupled with a flatsection 1429 of constant diameter. Passing through the B stage 1407 hasthe effect of again reducing a prosthetic heart valve diameter from afirst larger input value (the output diameter of the A stage 1405) to asecond smaller and final output value.

The internal mechanical components of the loading system 1401 aredisplayed in cross-sectional view in FIG. 15. As a valve is pushed fromthe B stage 1407 to the C stage 1409, it retains the output diameterthat was set in the B stage 1407. In order to deflect certain portionsof the heart valve such as commissures, anchors or otherwise necessarylocating features, spring loaded actuators 1404 must be depressed, theact of which transfers linear displacement to the locating features ofthe prosthetic valve. Spring loaded actuators 1404 may be arranged invariably different circumferential configurations, for example three ofsuch actuators 1404 could be equally spaced by 120′ in order to deflectthree separate locating features of a heart valve prosthesis. Let thisdesign by no means be limited to three of such actuators, or anyspecific positioning scheme, as the design can be modified toincorporate any reasonable number and position of such actuatorsoperating on specific portions of stents. By travelling through aconstant diameter channel 1430 in the C stage 1409, a prosthetic heartvalve can be brought into contact with the tips 1420 of the springloaded actuators 1404. The spring loaded actuator 1404 is comprised of abutton 1419 which can be depressed, a shaft 1418 on which a spring 1411is housed, a shoulder 1421 against which the spring 1411 abuts toprovide return force, a cylindrical pocket 1441 in which the spring 1411has room to compress, and bearing surfaces 1442 which allow the shaft1418 to translate freely between an uncompressed and a compressed state,and a tip 1420 that protrudes out of a hole 1412 and comes into contactwith a heart valve to permit compression.

As seen in FIG. 16, a capping plate 1410 is fastened to the C stage 1409by threaded fasteners 1413. The capping plate 1410 acts with the C stage1409 to house the springs 1411 and spring loaded actuators 1404.

FIG. 17 illustrates the manner through which the A stage 1405, the Bstage 1407 and the C stage 1409 are combined, and details the locationsof relevant attachment mechanisms as discussed previously.

As seen in FIG. 18A, the end view of the C stage 1409 has an outletorifice 1403. An uncompressed diametral circle 1422, representing theinitial large diameter at which the tips 1420 of the spring loadedactuators 1404 are normally located is also illustrated. It is thenshown in FIG. 18B that upon actuation, the tips 1420 of the springloaded actuators 1404 translate and conform to a smaller, compresseddiametral circle 1423. This is the mechanism through which selectiveprosthetic valve deflection is achieved in order to mate portions of theprosthetic valve with the delivery system.

One of skill in the art will appreciate that the loading device is notlimited to three separate housings. Alternative embodiments of thedevice may include a single housing that incorporates some or all of thefeatures of the three individual housings. Single housing embodimentsare illustrated in FIGS. 27-33 and described below. An exemplaryembodiment of a single housing loading device is described in greaterdetail below. Other alternative embodiments may include either the A orB housing and the C housing, and this configuration may be as twocouplable housings, or a single integrated housing. In still otherembodiments, the entire diameter reduction may be accomplished with asingle tapered channel in a single housing and the selective deflectionmay be in that same housing or in a separate housing. One of skill inthe art will appreciate that any combination or permutation of the threehousings and their corresponding features may be used in a loadingdevice to load a prosthesis onto a delivery system.

FIGS. 19-26B illustrate an exemplary method of using the loading devicedescribed above for loading a prosthetic valve such as those describedherein onto a delivery system such as those described herein. FIG. 19illustrates the initial interaction between the A stage 1405 and ageneric prosthetic heart valve 1424. In this example, the generic heartvalve 1424 includes three anchoring tabs 1425 which are required forlocation and attachment of this valve model to a delivery system. Thesethree anchoring tabs 1425 may be equivalent to the commissure posts orstruts previously described above with respect to the disclosedprosthetic mitral valve. As the generic prosthetic heart valve 1424 ismanually pushed through the A stage 1405, the valve slides down aninternally tapered section 1426, past a filleted transition zone 1439,and into a flat section 1428 of constant diameter. In order to safelyreduce the diameter of a heart valve prosthesis that is at leastpartially manufactured from alloys such as Nitinol it is first necessaryto cool the prosthesis in chilled saline, in order to bring the devicebelow a temperature known as the austenitic finish temperature, which isspecific to each alloy and dependant upon manufacturing processes. Thisis the temperature at which the crystalline structure of Nitinol becomesarranged in a manner that allows for plastic deformation, with littlerisk of permanent damage due to strain. When the generic prostheticheart valve 1424 is positioned in the flat section 1428 and manuallyadjusted to acquire a circular shape, the A stage 1405 is ready to beattached to the B stage 1407, and this step of the procedure will bedetailed below.

As shown in FIG. 20, the A stage 1045 is latched onto the B stage 1407by way of pressing cantilevered tabs 1415 on the A stage 1405 that endin snap fits 1417 into respective locking windows 1416 that reside onthe B stage 1407. After latching the A stage 1405 onto the B stage 1407,the generic prosthetic heart valve 1424 can be advanced across thejunction and into an internally tapered section 1427, past a filletedtransition zone 1440 and finally into a flat section 1429 of constantand final diameter. This step of the procedure can be more readilyappreciated if viewed in FIG. 21, as it becomes necessary to detach theA stage 1405 from the B stage 1407 as the generic prosthetic heart valve1424 assumes its end location in the B stage 1407.

As shown in FIG. 22, the B stage 1407 is latched onto the C stage 1409by way of pressing cantilevered tabs 1415 on the B stage 1407 that endin snap fits 1417 into respective locking windows 1416 that reside onthe C stage 1409. After latching the B stage 1407 onto the C stage 1409,the generic prosthetic heart valve 1424 can be advanced across thejunction and into a flat section 1430 of constant and final diameter.The diameter of the flat section 1430 is designed to optimally compressthe valve 1424 to the smallest diameter that would still allow passageof a respective delivery system or components thereof, and still allowaccess to the relevant stent features required for valve loading andanchoring to the delivery system.

The final compressed location of a generic prosthetic heart valve 1424within the C stage 1409 can be seen in FIG. 23. Before accurateanchoring tab 1425 deflection can be performed, it may first benecessary to rotate the valve 1424 within the flat section 1430 ofconstant diameter so as to align all anchoring tabs 1425 with the tips1420 of respective spring loaded actuators 1404. This practice isillustrated in FIG. 23. After performing anchoring tab 1425 alignment,accurate spring loaded actuator 1404 operation becomes possible.

As can be seen in FIG. 24, a generic delivery system 1432 can beintroduced to the outlet orifice 1403 of the C stage 1409, and retainingpockets (also referred to herein as receptacles or slots) 1434 locatedin an anchoring hub 1433 can be brought into alignment with theanchoring tabs 1425 of a generic prosthetic heart valve 1424.

FIG. 25 illustrates the mechanism by which the tips 1420 of the springloaded actuators 1404 are pressed into the anchoring tabs 1425 of ageneric prosthetic heart valve 1424, so as to deflect them by bending,and force the anchoring tabs 1425 into respective retaining pockets 1434located in the anchoring hub 1433 of a generic delivery system 1432.

FIG. 26A shows an end view of the C stage 1409, with a prosthetic heartvalve 1444 such as those previously described above, compressed and inplace prior to final deflection. Relevant features of the prostheticheart valve 1444 include the ventricular skirt 1435, trigonal tabs 1436,and commissure anchors (also referred to as commissure posts or struts)1437, details of which can be found elsewhere in this specification.

FIG. 26B shows an end view of the C stage 1409, with a prosthetic heartvalve 1444 compressed and in place after final deflection. Note thatrelevant features such as the ventricular skirt 1435, and trigonal tabs1436 have not been displaced by any portion of the spring loadedactuators 1404, and that only the commissure anchors 1437 have beendisplaced to a final reduced diameter and made available to respectivefeatures on the respective delivery system, details of which aredisclosed elsewhere in this specification. Once the commissure anchors1437 have been deflected radially inward and positioned in thecorresponding receptacles on the delivery catheter, an outer shaft orsheath may be slidably disposed thereover in order to capture thecommissure anchors. Another outer shaft or sheath may then be slidablydisposed over the remainder of the prosthetic valve to capture it andhold it in position during delivery. Release of the prosthetic valve isdescribed below.

FIGS. 27-29B illustrate another exemplary embodiment of a loadingsystem. While this embodiment is similar to the embodiment previouslydescribed, this embodiment has the advantage of providing support toboth internal and external surfaces of the prosthesis during loading,and also the actuators are simultaneously actuated.

As seen in FIG. 27, a variation of the valve loading system is detailed.An inner cone 2701 provides support for the internal surface of a valveor prosthesis to be loaded. The important features of inner cone 2701include a conical inclined plane 2702, and twistable locking mechanism2703 such as a bayonet lock. The conical inclined plane 2702 aids inseating a valve to be loaded, while the twistable locking mechanism 2703allows the inner cone 2701 to be securely fastened to an outer cone2704, through a twisting motion that will be further described below.

Three locking pegs 2705 on the circumference of the outer cone 2704allow the base of the outer cone 2704 to be mated to the lockingmechanism 2703 of the inner cone 2701. A threaded section 2706 of theouter cone 2704 begins at an initial end 2709 and terminates at a finalend 2710, and is threaded in a manner that allows for mating to adisplacement nut 2708 which has matching internal threads. As thedisplacement nut 2708 is screwed forward from initial end 2709 to finalend 2710, the leading edge of the displacement nut 2708 forces a fin orother finger-like member 2707 to be pushed down due to the inclinedplane that comprises the rib 2713 of the fin 2707, and the slidingmotion of the displacement nut 2708 as it rides over the fin 2707. Aplurality of fins 2707 may be spaced circumferentially about the outercone 2708 at the final end 2710 in order to affect the desiredmechanism. This embodiment preferably has three fins spaced generally120 degrees apart.

As seen in FIG. 28A and FIG. 28B, end views of the device providefurther detail of the inherent mechanical relationships between relevantparts. Pad 2714 is seen in FIG. 28B resting in an un-deflected position2711. As the displacement nut 2708 rides over the threaded section 2706,the position of pad 2714 moves radially inward to a deflected position2712, as seen in FIG. 29A. A plurality of pads 2714 may be spacedcircumferentially about the outer cone 2708 at the final end 2710 inorder to affect the desired mechanism in conjunction with an equalplurality of fins 2707.

FIGS. 30-33 illustrate another exemplary embodiment of a loadingfixture. FIG. 30 is a perspective view of the loading system. Thefingers 2707 a are thicker than previous embodiments and also have acammed profile instead of a ramped profile. Also, the displacement nut2708 a is thinner than previous embodiments. These features help theoperator to smoothly actuate the displacement nut and radially collapsea portion of the prosthesis for loading onto a delivery system.Additionally, this embodiment includes a “D” shaped flange 3001 on theinlet side of the cone (this feature can also be seen in FIG. 33) whichcan be used for valve alignment purposes. Other alignment features willbe illustrated in FIGS. 31-32. Thus the operator will know that the flatportion of the “D” shaped flange is also the flat portion of the “D”shaped prosthesis.

FIG. 31 is an isometric view of the loading cone with the displacementnut removed, illustrating optional features which may be used in any ofthe loading fixture embodiments. A vertical slot 3102 appearing on thetapered portion of the loading cone acts as a landmark for a suture (notillustrated) on the prosthetic valve to be aligned with. This allows thevalve to be accurately located during loading. A horizontal slot 3103appearing on the tapered transition portion of the loading cone acts asa landmark with which the atrial skirt region of the stent can beregistered against, in order to accurately locate the valve prior tocommissure capture. The loading cone may be formed of an optically clearpolymer such as polycarbonate which allows the user to see valvefeatures/landmarks throughout the loading process.

FIG. 32 is an isometric view of the loading cone. An optional sizedesignation 3004 has been stamped on the tapered section of the coneadjacent to the D-shaped flange 3001. Indicia allow a user to easilyidentify and select the appropriate loading fixture.

FIG. 33 is an end view of the loading cone. The D-shaped flange 3001 canclearly be seen in this view. When loading a valve into the loadingcone, an operator may orient the flat side of the valve with the flatportion of the D-shaped flange prior to insertion.

The embodiment of FIGS. 30-33 provides a single stage for collapsing aprosthetic valve and therefore is easier than a multiple stage loadingfixture. The prosthetic valve may be chilled in cold saline duringloading as previously discussed above. Because this embodiment issmaller and has fewer parts than other embodiments, it is lighter andeasier to use, and also manufacturing costs are reduced. It may beactuated with a single hand while other embodiments may require morethan one hand.

Delivery Method. A number of methods may be used to deliver a prostheticcardiac valve to the heart. Exemplary methods of delivering a prostheticmitral valve may include a transluminal delivery route which may also bea transseptal technique which crosses the septum between the right andleft sides of the heart, or in more preferred embodiments, a transapicalroute may be used such as illustrated in FIGS. 12A-12L. The deliverydevice previously described above may be used to deliver any of theembodiments of prosthetic valves described herein, or other deliverydevices and other prosthetic valves may also be used, such as thosedisclosed in U.S. patent application Ser. No. 13/096,572, previouslyincorporated herein by reference. However, in this preferred exemplaryembodiment, the prosthetic cardiac valve of FIG. 6 is used so that theanterior tabs deploy first, followed by the posterior tab, and then theventricular skirt.

FIG. 12A illustrates the basic anatomy of the left side of a patient'sheart including the left atrium LA and left ventricle LV. Pulmonaryveins PV return blood from the lungs to the left atrium and the blood isthen pumped from the left atrium into the left ventricle across themitral valve MV. The mitral valve includes an anterior leaflet AL on ananterior side A of the valve and a posterior leaflet PL on a posteriorside P of the valve. The leaflets are attached to chordae tendineae CTwhich are subsequently secured to the heart walls with papillary musclesPM. The blood is then pumped out of the left ventricle into the aorta Aowith the aortic valve AV preventing regurgitation.

FIG. 12B illustrates transapical delivery of a delivery system 1202through the apex of the heart into the left atrium LA. The deliverysystem 1202 may be advanced over a guidewire GW into the left atrium,and a tissue penetrating tip 1204 helps the delivery system pass throughthe apex of the heart by dilating the tissue and forming a largerchannel for the remainder of the delivery system to pass through. Thedelivery catheter carries prosthetic cardiac valve 1208. Once the distalportion of the delivery system has been advanced into the left atrium,the outer sheath 1206 may be retracted proximally (e.g. toward theoperator) thereby removing the constraint from the atrial portion of theprosthetic valve 1208. This allows the atrial skirt 1210 to self-expandradially outward. In FIG. 12C, as the outer sheath is further retracted,the atrial skirt continues to self-expand and peek out, until it fullydeploys as seen in FIG. 12D. The atrial skirt may have a cylindricalshape or it may be D-shaped as discussed above with a flat anteriorportion and a cylindrical posterior portion so as to avoid interferingwith the aortic valve and other aspects of the left ventricular outflowtract. The prosthetic cardiac valve may be advanced upstream ordownstream to properly position the atrial skirt. In preferredembodiments, the atrial skirt forms a flange that rests against asuperior surface of the mitral valve and this anchors the prostheticvalve and prevents it unwanted movement downstream into the leftventricle.

As the outer sheath 1206 continues to be proximally retracted, theannular region of the prosthetic cardiac valve self-expands next intoengagement with the valve annulus. The annular region also preferablyhas the D-shaped geometry, although it may also be cylindrical or haveother geometries to match the native anatomy. In FIG. 12E, retraction ofsheath 1206 eventually allows both the anterior 1212 and posterior 1214tabs to partially self-expand outward preferably without engaging theanterior or posterior leaflets or the chordae tendineae. In thisembodiment, further retraction of the outer sheath 1206 then allows boththe anterior tabs 1212 (only one visible in this view) to complete theirself-expansion so that the anterior leaflet is captured between an innersurface of each of the anterior tabs and an outer surface of theventricular skirt 1216, as illustrated in FIG. 12F. The posterior tab1214 remains partially open, but has not completed its expansion yet.Additionally, the tips of the anterior tabs also anchor into the leftand right fibrous trigones of the mitral valve, as will be illustratedin greater detail below.

In FIG. 12G, further retraction of the outer sheath 1206 then releasesthe constraints from the posterior tab 1214 allowing it to complete itsself-expansion, thereby capturing the posterior leaflet PL between aninner surface of the posterior tab 1214 and an outer surface of theventricular skirt 1218. In FIG. 12H, the sheath is retracted furtherreleasing the ventricular skirt 1220 and allowing the ventricular skirt1220 to radially expand outward, further capturing the anterior andposterior leaflets between the outer surface of the ventricular skirtand their respective anterior or posterior tabs. Expansion of theventricular skirt also pushes the anterior and posterior leafletsoutward, thereby ensuring that the native leaflets do not interfere withany portion of the prosthetic valve or the prosthetic valve leaflets.The prosthetic valve is now anchored in position above the mitral valve,along the annulus, to the valve leaflets, and below the mitral valve,thereby securing it in position.

Further actuation of the delivery device now retracts the outer sheath1206 and the bell catheter shaft 1222 so as to remove the constraintfrom the hub catheter 1224, as illustrated in FIG. 12I. This permits theprosthetic valve commissures 1226 to be released from the hub catheter,thus the commissures expand to their biased configuration. The deliverysystem 1202 and guidewire GW are then removed, leaving the prostheticvalve 1208 in position where it takes over for the native mitral valve,as seen in FIG. 12J.

FIGS. 12K and 12L highlight engagement of the anterior and posteriortabs with the respective anterior and posterior leaflets. In FIG. 12K,after anterior tabs 1212 have been fully expanded, they capture theanterior leaflet AL and adjacent chordae tendineae between an insidesurface of the anterior tab and an outer surface of the ventricularskirt 1220. Moreover, the tips 1228 of the anterior tabs 1212 areengaged with the fibrous trigones FT of the anterior side of the mitralvalve. The fibrous trigones are fibrous regions of the valve thus theanterior tabs further anchor the prosthetic valve into the native mitralvalve anatomy. One anterior tab anchors into the left fibrous trigone,and the other anterior tabs anchors into the right fibrous trigone. Thetrigones are on opposite sides of the anterior side of the leaflet. FIG.12L illustrates engagement of the posterior tab 1214 with the posteriorleaflet PL which is captured between an inner surface of the posteriortab and an outer surface of the ventricular skirt 1220. Additionally,adjacent chordae tendineae are also captured between the posterior taband ventricular skirt.

FIGS. 13A-13L illustrate another exemplary embodiment of a deliverymethod. This embodiment is similar to that previously described, withthe major difference being the order in which the prosthetic cardiacvalve self-expands into engagement with the mitral valve. Any deliverydevice or any prosthetic cardiac valve disclosed herein may be used,however in preferred embodiments, the embodiment of FIG. 7 is used.Varying the order may allow better positioning of the implant, easiercapturing of the valve leaflets, and better anchoring of the implant.This exemplary method also preferably uses a transapical route, althoughtransseptal may also be used.

FIG. 13A illustrates the basic anatomy of the left side of a patient'sheart including the left atrium LA and left ventricle LV. Pulmonaryveins PV return blood from the lungs to the left atrium and the blood isthen pumped from the left atrium into the left ventricle across themitral valve MV. The mitral valve includes an anterior leaflet AL on ananterior side A of the valve and a posterior leaflet PL on a posteriorside P of the valve. The leaflets are attached to chordae tendineae CTwhich are subsequently secured to the heart walls with papillary musclesPM. The blood is then pumped out of the left ventricle into the aorta AOwith the aortic valve AV preventing regurgitation.

FIG. 13B illustrates transapical delivery of a delivery system 1302through the apex of the heart into the left atrium LA. The deliverysystem 1302 may be advanced over a guidewire GW into the left atrium,and a tissue penetrating tip 1304 helps the delivery system pass throughthe apex of the heart by dilating the tissue and forming a largerchannel for the remainder of the delivery system to pass through. Thedelivery catheter carries prosthetic cardiac valve 1308. Once the distalportion of the delivery system has been advanced into the left atrium,the outer sheath 1306 may be retracted proximally (e.g. toward theoperator) thereby removing the constraint from the atrial portion of theprosthetic valve 1308. This allows the atrial skirt 1310 to self-expandradially outward. In FIG. 13C, as the outer sheath is further retracted,the atrial skirt continues to self-expand and peck out, until it fullydeploys as seen in FIG. 13D. The atrial skirt may have a cylindricalshape or it may be D-shaped as discussed above with a flat anteriorportion and a cylindrical posterior portion so as to avoid interferingwith the aortic valve and other aspects of the left ventricular outflowtract. The prosthetic cardiac valve may be advanced upstream ordownstream to properly position the atrial skirt. In preferredembodiments, the atrial skirt forms a flange that rests against asuperior surface of the mitral valve and this anchors the prostheticvalve and prevents it from unwanted movement downstream into the leftventricle.

As the outer sheath 1306 continues to be proximally retracted, theannular region of the prosthetic cardiac valve self-expands next intoengagement with the valve annulus. The annular region also preferablyhas the D-shaped geometry, although it may also be cylindrical or haveother geometries to match the native anatomy. In FIG. 13E, retraction ofsheath 1306 eventually allows both the anterior 1312 and posterior 1314tabs to partially self-expand outward preferably without engaging theanterior or posterior leaflets or the chordae tendineae. In thisembodiment, further retraction of the outer sheath 1306 then allows boththe anterior tabs 1312 (only one visible in this view) to complete theirself-expansion so that the anterior leaflet is captured between an innersurface of each of the anterior tabs and an outer surface of theventricular skirt 1316, as illustrated in FIG. 13F. The posterior tab1214 remains partially open, but has not completed its expansion yet.Additionally, the tips of the anterior tabs also anchor into the leftand right fibrous trigones of the mitral valve, as will be illustratedin greater detail below.

In FIG. 13G, further retraction of the outer sheath 1306 then releasesthe constraint from the ventricular skirt 1320 allowing the ventricularskirt to radially expand. This then further captures the anteriorlealflets AL between the anterior tab 1312 and the ventricular skirt1316. Expansion of the ventricular skirt also pushes the anterior andposterior leaflets outward, thereby ensuring that the native leaflets donot interfere with any portion of the prosthetic valve or the prostheticvalve leaflets. Further retraction of sheath 1306 as illustrated in FIG.13H releases the constraint from the posterior tab 1314 allowing it tocomplete its self-expansion, thereby capturing the posterior leaflet PLbetween an inner surface of the posterior tab 1314 and an outer surfaceof the ventricular skirt 1318. The prosthetic valve is now anchored inposition above the mitral valve, along the annulus, to the valveleaflets, and below the mitral valve, thereby securing it in position.

Further actuation of the delivery device now retracts the outer sheath1306 and the bell catheter shaft 1322 so as to remove the constraintfrom the hub catheter 1324, as illustrated in FIG. 13I. This permits theprosthetic valve commissures 1326 to be released from the hub catheter,thus the commissures expand to their biased configuration. The deliverysystem 1302 and guidewire GW are then removed, leaving the prostheticvalve 1308 in position where it takes over for the native mitral valve,as seen in FIG. 13J.

FIGS. 13K and 13L highlight engagement of the anterior and posteriortabs with the respective anterior and posterior leaflet. In FIG. 13K,after anterior tabs 1312 have been fully expanded, they capture theanterior leaflet AL and adjacent chordae tendineae between an insidesurface of the anterior tab and an outer surface of the ventricularskirt 1320. Moreover, the tips 1328 of the anterior tabs 1312 areengaged with the fibrous trigones FT of the anterior side of the mitralvalve. The fibrous trigones are fibrous regions of the valve thus theanterior tabs further anchor the prosthetic valve into the native mitralvalve anatomy. One anterior tab anchors into the left fibrous trigone,and the other anterior tabs anchors into the right fibrous trigone. Thetrigones are on opposite sides of the anterior side of the leaflet. FIG.13L illustrates engagement of the posterior tab 1314 with the posteriorleaflet PL which is captured between an inner surface of the posteriortab and an outer surface of the ventricular skirt 1320. Additionally,adjacent chordae tendineae are also captured between the posterior taband ventricular skirt.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

What is claimed is:
 1. A device for loading a prosthesis onto a deliverysystem, said device comprising: an inlet; an outlet; a central boreextending between the inlet and the outlet; one or more actuatorsdisposed adjacent the outlet and configured to actuate radially inwardand outward, wherein: the one or more actuators are configured to beactuated radially inward to selectively deflect a plurality ofengagement tabs of the prosthesis radially inward to mate the engagementtabs with the delivery system; and the one or more actuators areconfigured to deflect the engagement tabs radially inward to a firstdiameter while the prosthesis is at least partially compressed in thecentral bore to a second diameter; and the first diameter is less thanthe second diameter.
 2. The device of claim 1, wherein the central borecomprises a constant diameter region.
 3. The device of claim 1, whereinthe central bore comprises a tapered region adapted to radially collapsethe prosthesis from an initial diameter to a smaller diameter when theprosthesis is passed therethrough.
 4. The device of claim 1, wherein theone or more actuators comprise three actuators circumferentiallydisposed around the housing about every 120 degrees.
 5. The device ofclaim 1, wherein the one or more actuators are operably coupled togethersuch that the one or more actuators are actuated simultaneously.
 6. Thedevice of claim 1, further comprising a collar threadably engaged withthe housing and wherein rotating the collar actuates the one or moreactuators.
 7. The device of claim 1, wherein the one or more actuatorscomprise spring loaded actuators biased to return to a position disposedradially outward from the central bore.
 8. The device of claim 1,wherein the prosthesis comprises a prosthetic heart valve.
 9. The deviceof claim 1, wherein the prosthesis comprises the plurality of engagementtabs, and wherein actuation of the one or more actuators is adapted tomove the plurality of engagement tabs radially inward.
 10. The device ofclaim 9, wherein the plurality of engagement tabs are adapted to bereleasably engaged with retaining features on the delivery catheter. 11.The device of claim 9, wherein the prosthesis comprises a prostheticheart valve and the plurality of engagement tabs comprise commissureposts of the prosthetic heart valve.